"My apartment is one hundred and twenty square meters."
Translation:Mon appartement fait cent-vingt mètres carrés.
Firstly, it is simply "cent-vingt" - the one (un) is never said when referring to one hundred. Secondly, the French use the verb "faire " when speaking of measurements.
"ça fait 2 mètres de diamètre "
it's 2 metres in diameter
"la salle à manger fait 4 mètres par 3 "
the dining room measures 4 by 3 metres
please note that there's no hyphen between hundreds and tens, just between tens and units (exception: vingt et un, trente et un, quarante et un, cinquante et un, etc.)
- cent vingt (120)
- cent vingt et un (121)
- cent vingt-deux (122)
- deux mille (2 000)
- vingt-deux mille deux cent vingt-deux (22 222)
[edit: I just read about the Rectifications de l'orthographe de 1990. it seems that to simplify and standardize writing, they make it possible to hyphen all the words in numbers.... I'm seriously bewildered as I've never heard about it]